One type of vehicle licence plate, such as shown in WO 03/062 014 A1, includes an electroluminescent display which is energized by alternating current at a potentially harmful voltage of about 140V to 200V that is derived from a much lower voltage battery and alternator. The higher voltage is high enough to harm a person who touches a conductor carrying the voltage. The display includes a thin, flat carrier plate and a thin luminous “foil” that adheres to an outer face of the carrier plate. A connector for carrying the higher voltage to the luminous foil should itself be thin and should prevent any person or object from engaging conductors that carry the higher voltage. Such protection against engagement by a person or object should remain even if the license plate that includes the carrier plate with luminous foil thereon, should not be present.